Late Show host Stephen Colbert appeared to take over a microphone at the Republican National Convention in Cleveland to mock presumptive presidential nominee Donald Trump, before he was quickly escorted off stage by security.

The 52-year-old late-night host, in town to do live coverage of the convention for his struggling CBS program, was dressed in costume as Caesar Flickerman from the Hunger Games movies.

“[Trump] has formed an alliance with Indiana Governor Mike Pence,” Colbert began, before pausing and bowing his head for a moment as if he’d fallen unconscious. “Sorry, I blacked out there for a moment.”

“So it is my honor to hereby launch and begin the 2016 Republican National hungry for power games!” Colbert bellowed while banging a large gavel on the lectern, before he was approached by a security guard.

“Look, I know I’m not supposed to be here, but let’s be honest, neither is Donald Trump,” Colbert managed to sneak in before he was escorted off stage.

It wasn’t immediately clear whether the stunt was spontaneous or planned in advance. The bit was most likely filmed for Colbert’s Late Show, which begins two weeks of live broadcasts from both the Republican and Democratic conventions on Monday.

As Breitbart News reported Sunday, it’s all hands on deck at CBS’ Late Show as Jon Stewart is scheduled to appear on the program during Monday night’s broadcast. The move to add Stewart is almost certainly an attempt to shake Colbert’s program out of its long-running ratings nightmare.